Hydraulic device

ABSTRACT

A hydraulic motor having a stator with alternately inwardly and outwardly, radially extending reaction surfaces, a rotor disposed within said stator and having a plurality of chambers in its peripheral surface elongated in the direction of the axis of the rotor, and slippers disposed in each of the chambers for reciprocating movement therein. Each slipper has a recess in the surface facing the reaction surfaces, and a rolling element disposed in each recess contacts the reaction surface. Relative movement between the stator and rotor causes a tilting action of the slipper which is utilized to form a contact seal between the side of the slipper and the side walls of the chambers. Lubricating channels may be provided in the surface of the recess to lubricate the rolling element, utilizing the hydraulic fluid communicated to the channels by passages in the slipper. While the hydraulic device is intended primarily for use as a motor, the principles involved in the motor may be utilized effectively in a pump.

United States Patent 1191 Eddy 14 1 May 20, 1975 HYDRAULIC DEVICE RobertT. Eddy, South Bend, Ind.

[73] Assignee: Reliance Electric Company,

Mishawaka, Ind.

[22] Filed: Apr. 19, 1973 [21] Appl. No.: 352,424

[75] Inventor:

2,292,181 4/1942 Tucker..... 91/488 2,459,786 1/1949 Beaman i I 91/4992,612,110 9/1952 Delegard 417/204 2,712,794 7/1955 Humphreys..... 91/4723,046,950 7/1962 Smith 91/498 3,699,848 10/1972 Prendergast.... 91/4873,724,334 4/1973 Denker 91/491 FOREIGN PATENTS OR APPLICATIONS 679,7682/1964 Canada 1. 417/204 1,133,388 11/1956 France 92/172 PrimaryExaminer-William L. Freeh Attorney, Agent, or FirmMarmaduke Hobbs Hobbs& Green 1 71 ABSTRACT A hydraulic motor having a stator with alternatelyinwardly and outwardly, radially extending reaction surfaces, a rotordisposed within said stator and having a plurality of chambers in itsperipheral surface elongated in the direction of the axis of the rotor,and slippers disposed in each of the chambers for reciprocating movementtherein. Each slipper has a recess in the surface facing the reactionsurfaces, and a rolling element disposed in each recess contacts thereaction surface. Relative movement between the stator and rotor causesa tilting action of the slipper which is utilized to form a Contact sealbetween the side of theslipper and the side walls of the chambers.Lubricating channels may be provided in the surface of the recess tolubricate the rolling element, utilizing the hydraulic fluidcommunicated to the channels by passages in the slipper. While thehydraulic device is intended primarily for use as a motor, theprinciples involved in the motor may be utilized effectively in a pump.

13 Claims, 8 Drawing Figures HYDRAULIC DEVICE In hydraulic systems,conventional vane and gear type hydraulic motors and gcrotor motors areextensively used and will perform satisfactorily under normal operatingconditions, and will have a reasonably long operating life at low andmoderate hydraulic pressures. However, at relatively high pressuresthese motors fre quently have only a limited life, and their efficiencyis often impaired within a relatively short time at the higherpressures. The parts of these conventional motors often are subjected toexcessive wear at normal pressures, and in order to obtain the requiredoperating efficiency, relatively close tolerances must be maintained infabricating the motor parts. Further, under certain conditions ofoperation. such as when the motor is being driven by the equipment,normally driven by the motor, cavitation may occur in the hydraulicsystem anterior to the motor which may place an undue burden on theequipment and system or render the system inoperative. It is thereforeone of the principal objects of the present invention to provide ahydraulic motor which can be operated efficiently under high pressureand at high torque for extended periods of time without failure, andwhich is so constructed and designed that the parts thereof have a longlife throughout the normal pressure operating range.

Another object of the invention is to provide a motor having a pluralityof reaction elements, which will not become pumping elements in theevent the equipment, normally driven by the motor, drives the motor, andwhich hence will not cause cavitation in the hydraulic lines of thesystem, but rather becomes free wheeling whenever the foregoingcondition develops in the motor-equipment installation, thus minimizingthe braking action of the motor during such operating conditions.

Still another object is to provide a relatively simple, compact andversatile hydraulic motor having a series of reciprocating elementsforming a pressure responsive means in individual chambers, which have aslipper-type wear compensating and fluid sealing structure, forincreasing the operating efficiency and extending the effective life ofthe elements, and which is easily serviced and repaired to maintain themotor in optimum operating condition.

A further object is to provide a motor of the aforementioned type havinga stator and a rotor in which the rotor and the output shaft thereforare hydraulically balanced.

Additional objects and advantages of the invention will become apparentfrom the following description and accompanying drawings, wherein:

FIG. 1 is an elevational view of the present hydraulic motor;

FIG. 2 is an enlarged crosssectional view of the hydraulic motor shownin FIG. 1, the section being taken on line 2 2 of the latter figure;

FIG. 3 is a transverse cross-sectional view of the hy draulic motorshown in the preceding figures, the section being taken on line 3 3 ofFIG. 2;

FIG. 4 is a cross-sectional view of the hydraulic motor, the sectionbeing taken on line 4 4 of FIG. 2;

FIG. 5 is a fragmentary cross-sectional view of the rotor, the sectionbeing taken on line 5 5 of FIG. 4;

FIG. 6 is an enlarged diagrammatical view of one of the cylinders of themotor, illustrating the operation of the piston and slipper type sealincorporated therein;

FIG. 7 is an enlarged detail view ofa slightly modified form of theslipper used in the device shown in the preceding figures; and

FIG. 8 is a side elevational view of the slipper shown in FIG. 7.

Referring more specifically to the drawings, numeral 10 indicatesgenerally the present hydraulic motor having fluid inlet passage 12,fluid outlet passage 14, and power output shaft 16. While thedescription is directed to the present device as a hydraulic motor, itmay be used as a hydraulic pump if desired with few or no changes in thebasic structure thereof; however, the description hereinwill be directedprimarily to the use of the device as a hydraulic motor. The system inwhich the motor is used normally includes a hydraulic pump for providingthe necessary hydraulic pressure through a line from the pump to inlet12 and a return line connected to outlet 14. The system, including themotor and the pump which is normally driven by an electrical motor or anengine, may be used to drive a variety of different types of machines orequipment, connected to shaft 16 of the hydraulic motor.

The motor 10 consists of a rotor 20 having a plurality of fluid chambers22 and rolling elements 24 in the fluid chambers operating in effect aspistons. The rotor is mounted on output shaft 16 and secured thereto bykey 26 disposed in key-ways 28 and 30 in the rotor and shaft,respectively. The rotor is disposed in a stationary stator 40 orreaction member, the external part of which forms the periphery ofhousing 42 which includes end sections 44 and 46 and intermediatesection or port ring 48. The four sections 40, 44, 46 and 48 are securedtogether to form a rigid housing structure by a plurality of bolts 50extending through holes in the sections and being threadedly received inholes 52 in section 44, and the sections are preferably sealed bygaskets such as O-rings 49. Shaft 16 is journaled in bearings 54 and 56disposed in annular recesses in the internal face of sections 44 and 46,the shaft being sealed by an annular seal 58 in the enlarged opening 60through the end section 44 in which the shaft rotates. The shaft is heldagainst end-wise axial movement by a collar 62 engaging bearing 54 andshoulder 64 engaging bearing 56, and the outer end of shaft 16 isprovided with a key and key-way in order to connect the shaft to thedriven mechanism or equipment. A sheave, gear, or other drivetransmission element may be mounted on the shaft, or the shaft may becoupled directly to the input shaft of the driven equipment.

The chambers 22 in rotor 20 consist of slots extendlng across theperiphery of the rotor, and the rolling elements 24 are adapted toreciprocate therein from the internal end of the chamber, as viewed inthe one at the top of FIG. 4, to their fully extended position asillustrated by the two cylinders in approximately the 4 and 8 oclockpositions as viewed in FIG. 4. The rolling elements are forced outwardlyby the pressure in the chambers on the internal side of the elements 24and the elements react against the increasing surfaces of each lobe 72on the cam surface of reaction member 40. When the pressure is relievedin chambers 22, the fluid is ejected therefrom through outlet 14 at arelatlvely low pressure, as the rolling elements 24 engage decreasingcam surfaces 74. The number of lobes 72 on the cam surface is differentfrom the number of chambers and rolling elements, either greater orfewer in number, in order to maintain a uniform operation in the device.The rolling elements 24 are cylindrical in shape and are substantiallythe same length as the width of rotor and form a relatively snug fit atthe ends between sections 44 and 48, as seen in FIG. 2, thus eliminatingor minimizing the flow of fluid from the inner end of chambers 22 to thespace 80 between lobes 72, although some fluid may seep into the spaces80, and a drain is provided therefor. The spaces are connected to oneanother by an annular passage 81 in the inner face of section 44. Thefluid finding its way into space 80 is removed by a drain passage 82extending inwardly to a transverse passage 84 adjacent shaft 16. Thistransverse passage communicates with a drain cavity 86 which is in turndrained by a conduit (not shown) connected to cavity 86 through threadedhole 88. Thus the fluid is not permitted to build up a back pressure inthe spaces 80, which might otherwise react against the rolling elementsand interfere with the proper operation of the motor.

Chambers 22 are alternately connected to the high pressure inlet 12 andlow pressure outlet 14 by ports 90 and 92 in port plate or section 48,the ports 90 being connected by an annular groove 96 in section 46 withinlet port 12, and ports 92 being connected by annular groove 94 insection 46 with outlet port 14. When chambers 22 are communicating withports 90, the rolling elements 24 are traversing outwardly extendinginclines 70 of the cam surface on the stator, and when the chambers arein communication with ports 92, the rolling elements are traversinginwardly extending surfaces 74. The rolling elements are urged outwardlyby the high pressure transmitted to the chamber from conduit 12 andports 90, against the inclined surfaces 70, thus 1 causing rotationalmovement of rotor 20. The inwardly inclined portions 74 return therolling elements to the inner ends of chambers 22, causing the fluid inthe chambers to be ejected through ports 92 and low pressure outlet 14.The rotor is hydraulically balanced by the transmittal of hydraulicfluid to the side of the rotor 20 opposite ports 90 and 92. These portsare connected by a passage 100 extending completely through the rotor toslots 102 which are shown as located in the surface of section 44, butwhich may be located in the respective side of the rotor. Passage 100transmits the pressure of either ports 90 or ports 92 to the oppositeside of the rotor, and since slots 102 communicate with passage 100, thepressure of the fluid received from passage 100 is applied to the lefthand side of the rotor as viewed in FIG. 2, i.e. to the side oppositethe side on which the ports 90 and 92 are located. The slots 102 arepositioned with respect to ports 90 and 92 in such a way as to vary thepressure in response to the varying communication of chambers 22 withone or the other of ports 90 or 92. Thus each of the slots 102 containsfluid under a pressure representing the pressure being applied at theparticular moment on the opposite side of the rotor.

Rolling elements 24 are mounted in slippers 110 which in turn aremounted in chambers 22. The primary advantage of the combination rollingelement and slipper is the ability of the slipper to maintain aneffective seal between the side walls in the rotor defining chambers 22.The slipper is so constructed that an effective sealing contact ismaintained by the pressure applied on the rolling elements as therolling elements reciprocate inwardly and outwardly in engagement withthe undulating cam surface. In a motor, as rotor 20 rotates in theclockwise direction and as the rolling element contacts surface 74, theslipper tends to rotate angularly in the counter clockwise direction, asviewed in FIG. 4, thus applying additional pressure at points or edges112 and 114 on the side walls of chamber 22. As seen in FIG. 6,decreasing cam surface 74 causes the slipper to rotate in clockwisedirection, hence causes points or edges 116 and 118 to be pressed intofirm and sealing engagement with the transverse side walls of thechambers. Thus an effective seal is maintained throughout the length ofthe slippers, regardless of whether the rolling elements are driving therotor or are being driven by the cam surface to expel the low pressurefluid in the chamber. This operation takes place effectivelynotwithstanding any normal wear which may occur either in the side wallsof the slipper or in the side walls of the rotor defining chambers 22,in that any wear occurring in either the side walls of the chambers orin the sides of the slipper is compensated for by further tilting orrotation of the slipper against or into the two opposed, straight sidewalls defining the champer.

In the slipper form illustrated in FIGS. 7 and 8 and identified bynumeral 110, lubricating grooves are provided so that the hydraulicfluid can effectively lubricate the cylindrical piston disposed inbearing recess 120. The system for lubricating the roller includes twolongitudinal grooves 122 and 124 spaced laterally from the center ofbearing recess 120, and grooves 126 and 128 in opposite ends of theslipper communicating with the ends of grooves 122 and 124,respectively. Hydraulic fluid is thus permitted to flow from chamber 22through grooves 126 and 128 at each end of slipper into grooves 122 and124 where it effectively forms a film on the inner surface of recessbetween the slipper walls and the rotating cylindrical element 24. Inorder to assure effective lubrication between the sides of the slipperand the straight, parallel sides of the chamber walls, a plurality ofgrooves 130 are provided on the sides of the slipper. While thesegrooves 130 assist in maintaining effective lubrication between theslipper walls of the chamber, they also assist in minimizing leakagewhich might tend to occur between the walls of the two slippers andcylinders as the slippers tilt or shift from one sealing position toanother.

In the operation of the present motor, with the motor being connected toa mechanism or other equipment to be driven thereby, the fluid istransmitted from a high pressure source to inlet 12. The high pressurefluid then passes through annular groove 96 and ports 90 into thechambers which are in communication with ports 90. These chamberscontain the rolling elements in contact with the outwardly extendinginclined portions 70 of the cam surface of the stator. The high pressureforcing the rolling elements outwardly causes the rotor to rotate in theclockwise direction, as viewed in FIG. 4. The chambers containing therolling elements in contact with the inwardly extending inclinedsurfaces 74 are in communication with the ports 92, which in turn are incommunication with groove 94 and outlet port 14. The movement of therolling elements inwardly on inclined surfaces 74 ejects the lowpressure fluid from chambers 22. As pointed out previously herein, inthis embodiment, fewer chambers 22 and rolling elements 24 are providedin the rotor than lobes 72 on the stator, so that there is a constantand uniform rotational movement of the rotor with substantially constantpressure being applied at spaced points around the periphery thereof asthe rolling elements react on inclined surfaces 70. As the rotorrotates, the pressure on opposite sides of the rotor is maintainedsubstantially equal in the manner previously described herein, by thefluid transmitted through passage 100 to the slots 102. Thus the rotoris hydraulically balanced on all principal axes.

While only one embodiment has been described in detail herein, variouschanges and modifications may be made without departing from the scopeof the invention.

I claim:

1. A hydraulic device comprising a stator means, a rotor means, one ofsaid means having a plurality of alternate outwardly and inwardly,radially extending reaction surfaces and the other of said means havinga plurality of fluid chambers with an opening facing said reactionsurfaces, a slipper disposed in each of said chambers for reciprocatingmovement therein and having a recess in the surface facing said reactionsurfaces, a rolling element disposed in said recess and contacting saidreaction surfaces, each of said slippers being tiltable to both sides ofthe radial center line of the respective roller by the motion betweenthe stator and rotor means to form a contact seal with both side wallsof its chamber, the side walls of said slippers having a curvature whichincreases the sealing contact pressure as the slipper tips further fromthe radial center line of the respective chamber, and fluid inlet andoutlet ports bein alternately connected with said chambers.

2. A hydraulic device as defined in claim 1 in which said stator meansis annular shaped and contains the outwardly and inwardly extendingreaction surfaces, and said rotor means is disposed within said statormeans, and said fluid chambers are disposed in said rotor means in theperiphery thereof.

3. A hydraulic device as defined in claim 1 in which said chambers areelongated in the axial direction of said rotor means and extend to theopposite edges of said means.

4. A hydraulic device as defined in claim 2 in which said chambers areelongated in the axial direction of said rotor means and extend to theopposite edges of said means.

5. A hydraulic device as defined in claim 3 in which said slippers aresubstantially the same length as said chambers and said rolling elementsare cylindrically shaped and substantially the same length as saidchambers.

6. A hydraulic device as defined in claim 4 in which said slippers aresubstantially the same length as said chambers and said rolling elementsare cylindrically shaped and substantially the same length as saidchambers.

7. In a hydraulic device having a stator means, a rotor means, one ofsaid means having a plurality of alternate outwardly and inwardly,radially extending reaction surfaces and the other of said means havinga plurality of fluid chambers with an opening facing said reactionsurfaces, said chambers being elongated in the axial direction of saidrotor means: a slipper element for said chambers having an elongatedbody of substantially the same axial length as the cylinders andelongated recess extending in the axial direction disposed in thesurface of said element and facing said reaction surfaces for receivinga rolling element, said slipper element being tiltable to both sides ofthe radial center line of the respective roller by the relative motionbetween said stator and rotor means to form a contact seal with bothside walls of the chamber, the side walls of said slippers having acurvature which increases the sealing contact pressure as the slippertips further from the radial center line of the respective chamber.

8. A slipper element as defined in claim 7 in which longitudinal groovesare provided in the side wall of said recess and a passage connects eachof said grooves with the respective fluid chamber for lubricating therolling element.

9. A slipper element as defined in claim 7 in which a longitudinalgroove is disposed on opposite sides of the external surface of saidslipper.

10. A hydraulic device as defined in claim 7 in which the chambers arein the rotor means, and said slipper element applies a fluid sealingforce to the walls of said rotor means defining the respective chamberas the rolling element supported by said slipper element engages saidalternately outward and inward reaction surfaces.

11. A hydraulic device as defined in claim 10 in which the wallsdefining said chamber in said rotor means extend axially from one sideof the rotor means to the other and are straight and parallel to oneanother in the area engaged by said slipper element.

12. A hydraulic device as defined in claim 11 in which opposite sides ofsaid slipper element firmly contact opposite walls of the respectivechamber when said slipper elements are tilted by the relative movementof the rotor means in the stator means.

13. A hydraulic device as defined in claim 12 in which opposite sides ofsaid slipper element contact opposite walls of the respective chamberwhen said slipper elements are tilted by the relative movement of therotor means in the stator means, with the margins of the longitudinalside edges of the slipper element forming the line of contact betweenthe slipper element and the sides of the respective chambers.

1. A hydraulic device comprising a stator means, a rotor means, one ofsaid means having a plurality of alternate outwardly and inwardly,radially extending reaction surfaces and the other of said means havinga plurality of fluid chambers with an opening facing said reactionsurfaces, a slipper disposed in each of said chambers for reciprocatingmovement therein and having a recess in the surface facing said reactionsurfaces, a rolling element disposed in said recess and contacting saidreaction surfaces, each of said slippers being tiltable to both sides ofthe radial center line of the respective roller by the motion betweenthe stator and rotor means to form a contact seal with both side wallsof its chamber, the side walls of said slippers having a curvature whichincreases the sealing contact pressure as the slipper tips further fromthe radial center line of the respective chamber, and fluid inlet andoutlet ports being alternately connected with said chambers.
 2. Ahydraulic device as defined in claim 1 in which said stator means isannular shaped and contains the outwardly and inwardly extendingreaction surfaces, and said rotor means is disposed within said statormeans, and said fluid chambers are disposed in said rotor means in theperiphery thereof.
 3. A hydraulic device as defined in claim 1 in whichsaid chambers are elongated in the axial direction of said rotor meansand extend to the opposite edges of said means.
 4. A hydraulic device asdefined in claim 2 in which said chambers are elongated in the axialdirection of said rotor means and extend to the opposite edges of saidmeans.
 5. A hydraulic device as defined in claim 3 in which saidslippers are substantially the same length as said chambers and saidrolling elements are cylindrically shaped and substantially the samelength as said chambers.
 6. A hydraulic device as defined in claim 4 inwhich said slippers are substantially the same length as said chambersand said rolling elements are cylindrically shaped and substantially thesame length as said chambers.
 7. In a hydraulic device having a statormeans, a rotor means, one of said means having a plurality of alternateoutwardly and inwardly, radially extending reaction surfaces and theother of said means having a plurality of fluid chambers with an openingfacing said reaction surfaces, said chambers being elongated in theaxial direction of said rotor means: a slipper element for said chambershaving an elongated body of substantially the same axial length as thecylinders and elongated recess extending in the axial direction disposedin the surface of said element and facing said reaction surfaces forreceiving a rolling element, said slipper element being tiltable to bothsides of the radial center line of the respective roller by the relativemotion between said stator and rotor means to form a contact seal withboth side walls of the chamber, the side walls of said slippers having acurvature which increases the sealing contact pressure as the slippertips further from the radial center line of the respective chamber.
 8. Aslipper element as defined in claim 7 in which longitudinal grooves areprovided in the side wall of said recess and a passage connects each ofsaid grooves with the respective fluid chamber for lubricating therolling element.
 9. A slipper element as defined in claim 7 in which alongitudinal groove is disposed on opposite sides of the externalsurface of said slipper.
 10. A hydraulic device as defined in claim 7 inwhich the chambers are in the rotor means, and said slipper elementapplies a fluid sealing force to the walls of said rotor means definingthe respective chamber as the rolling element supported by said slipperelement engages said alternately outward and inward reaction surfaces.11. A hydraulic device as defined in claim 10 in which the wallsdefining said chamber in said rotor means extend axially from one sideof the rotor means to the other and are straight and parallel to oneanother in the area engaged by said slipper element.
 12. A hydraulicdevice as defined in claim 11 in which opposite sides of said slipperelement firmly contact opposite walls of the respective chamber whensaid slipper elements are tilted by the relative movement of the rotormeans in the stator means.
 13. A hydraulic device as defined in claim 12in which opposite sides of said slipper element contact opposite wallsof the respective chamber when said slipper elements are tilted by therelative movement of the rotor means in the stator means, with themargins of the longitudinal side edges of the slipper element formingthe line of contact between the slipper element and the sides of therespective chambers.